View Full Version : rear axle to differential flange bolt grade?

09-16-2008, 07:29 PM
On any bolt that is under stress, I normally replace it as I go through my car to make repairs. I had to remove the four rear axle/differential bolts to install my new springs. What grade of bolts should I replace these with?

09-16-2008, 08:08 PM
If your the superstitious type might as well go 8 with metal locs.

Andrew Mace
09-16-2008, 08:26 PM
I agree with Don. For that matter, why replace them at all? are they damaged somehow? Sure, replace the nyloc nuts, but....

09-16-2008, 08:34 PM
Okay, because those bolts are holding in tension, and a little flex would be better than a SNAP. I recommend, based on Carroll Smiths hardware book finding good grade 5 bolts. They bend slightly more than an 8 does under the same pressure.

09-16-2008, 10:56 PM
In either case Kevin, make sure you use shoulder bolts. That is , you don't want fully threaded bolts with the threads running up through the junction of the flanges. If you can't find them in the right length, I'd re-use the original bolts.


09-17-2008, 12:24 AM
What he says is true, forgot to mention it, but to me it is a given.... Sorry bout that.

09-17-2008, 01:19 AM
There is nothing wrong with the bolts. I had that through various discussions on the forum that it was better to replace bolt after if they had been under tension or retightened numerous times before. Not really knowing what has been done to the car over the years, I thought it was just a good idea to replace them. The lock nuts are definately bad - they had either not been tightened correctly or backed off over time. I could spin all four bolts when I used my fingers - scary.

09-17-2008, 12:11 PM
plastic insert "nyloc" type nuts should be replaced every time they are removed...

09-17-2008, 12:11 PM
I have always reused the ones that came off of the car. Nuts are not reusable and actually are different from the oens that yopu buy in the sotre. They are shorter. Definitely use the proper type bolt. I would order them from the big three.